Ovarian Function General (not Finished)

Question 1

What are the different stages of ovarian follicular development?

Answer 1

Primordial follicle pool- resting follicles present from birth in our domestic animals (oocytes arrested in Prophase I of meiosis)

Recruitment- activation to grow

Growing follicles- either continue to develop or become Atretic

Question 2

What are the Stages of the growing follicle an how many granulosa cell layers are found in each?

Answer 2

Primary follicles (one granulosa cell=GC layer)
Secondary follicles (two or more GC layers)
Tertiary (antral) follicles (fluid filled)
Then selected dominant follicle
Then ovulatory dominant follicle

(On anki)

Question 3

What are preantral follicles?

Answer 3

Follicles before they have reached the antral stage- still arrested oocyte in prophase 1 but growing in size

Question 4

What are small antra follicles?

Answer 4

Oocytes fully grown (1-5mm), can now resume and complete meiosis and get fertilised if given a surge

Question 5

What stage of follicle development is growth factor dependant?

Answer 5

Initial stage

Question 6

What do antral stage follicles depend on?

Answer 6

two gonadotrophins, first FSH, then LH

Question 7

What is the FSH and LH function in early stages of follicle development?

Answer 7

Proliferative function

Question 8

What is the FSH and LH function in later (mid) stages of follicle development?

Answer 8

Relating synthesis of steroid hormones progesterone ad cholesterol
Involved in follicular synthesis of Oestradiol

Question 9

Early to small antral follicles begin to produce steroid hormones which are…

Answer 9

-anti-apoptotic
-mitotic—>accelerates growth

Question 10

Progesterone acts as precursors for what? Which then develops into what?

Answer 10

Androgen, develops into Oestradiol

Question 11

Which enzyme converts androgen into Oestradiol?

Answer 11

Aromatase

Question 12

What is the role of gonadotrophins in the final stages of antral follicle development:

Answer 12

(Follicles dependant on FSH and LH)

-FSH rises to induce growth of all FSH-dependent small antral follicles present (‘cohort emergence’)
-The growing cohort follicles produce oestradiol and inhibin which in turn suppress FSH causing the FSH decline in circulation

Question 13

Cohort follicles are completely..

Answer 13

FSH dependant

Question 14

Is the dominant follicle (developed form cohort folicle) FSH dependant for growth?

Answer 14

Nope but is now LH dependant

Question 15

LH pulse frequency determines…

Answer 15

Dominant follicle growth and atresia

Question 16

Describe the stages of final maturation and ovulation of selected DG/large antral follicle

Answer 16

1. LH pulse frequency increases
2. DF Oestradiol synthesis and secretion increases rapidly
3. Rapid Oestradiol rise (via + feedback) induces the GnRH surge followed by LH/FSH surge
4. Causing maturation
   and then ovulation of DF = release of the oocyte

Question 17

Differences between species in how the GnRH surge for ovulation is induced

Answer 17

1) SPONTANEOUS eg cow; Rapid rise in oestradiol (sometimes with onset of luteinization of GC and TC) induces the GnRH surge or peak

2) INDUCED eg cats; A neuroendocrine reflex triggered by mating induces the GnRH surge in other words the cation of mating induces it